Guard device for syringes for use with heat-fluent materials



Dec. 5, 1950 H. F. BOEGER 2,532,598

GUARD DEVICE FOR SYRINGES FOR USE WITH HEAT-FLUENT MATERIALS Filed Dec.8, 1947 IN V EN TOR.

g/WA?? 1 77' T OIQNE V Patented Dec. 5, 1950 GUARD DEVICE FOR SYRINGESFOR USE WITH HEAT-FLUENT MATERIALS Henry F. Boeger', Beverly Hills,Califi, assignor to Surgident, Ltd West Los Angcles, Calif acorporationv of California Application December 8, 1947, Serial No.790,351

Claims.

This invention relates to a guard device for use with a syringecontaining heated materials and pertains particularly to a devicesuitable for use by a dental technician in conjunction with a syringefor injecting heat-fluent dental impression compositions, such ashydrocolloid compositions of the agar-agar type, into" cavities or toothpreparations, as in the technique of producing dental inlays.

These compositions, as is well known, have the characteristic ofcongealing to a resilient solid condition at a temperature at or nearbody temperature when cooled to such congealing temperature from aheated, fluent condition. To obtain. the desired fluent condition of thecomposition and at the sametime to sterilize the syringe, it is thepractice in the dental art to insert fragments or pieces of solidifiedimpression-rnaterial into a more-o-r-less conventional syringe, providedwith a hollow discharge needle at one end and adapted to receive aconventional plunger operating in a cylindrical cavity, put the plungerin place so as to close the cylindrical cavity, and placethe entiresyringe in boiling water and boil it for a sufficienttime to render thecontained impression-material suitably fluent. When, subsequently, thetechnician or dentist removes the syringe fromthe boiling water, it willbe understood that the syringe is at a temperature which makesit painfulfor the dentist to handle and painful tor the patient in the notinfrequent event that it comes into contact with his mouth tissues Sucha conventional syringe is usually provided with a discharge needledisposed at an angle to the length of the syringe to afiordbetter accessto all parts of the mouth, and with a. knob or handle on the outer end.of the plunger and a finger-grip on the body portion containing thecylindrical cavity.v The finger-grip is usually a small disc rigidlysecured to the body portion or to the cylinder head thereof, and iscircular so as to provide equal gripping surfaces at all angles andsmall so as not to obscure the dentists view of the patients mouth. Thedentist may hold such a syringe with the knob or handle pressed by histhumb or the heel of his hand and the body portion of the cylinder headgripped between two fingers which engage the finger grip. Flexion of thefingers will then press the plunger into the cylindrical cavity.- As theinstrument is symmetrical with the exception of the angular divergenceof the hollow needle, it may be so held that the needle is at anydesired angular relation to the dentists hand, but the constructionrequires that the hot body portion or cylinder head be firmly grippedbetween two fingers to control the direction of the discharge needle andprevent unnecessary contactof the syringe with the patients mouth. Inthese circumstances it is not extraordinary that discomfort to thedentist or practitioner may result in added discomfort to the patient,or that fiinching by the patient sets in motion a chain reaction inwhich he suffers doubly.

Having in mind the above outlined status of the art, it is a particularobject of the invention to provide a guard device for a syringe whichwill enable the dentist or practitioner to handle the syringe withoutdiscomfort to himself and to direct the discharge needle of the syringeto a desired location in the patients mouth without danger of contactingthe patient with the heated mass of the syringe body.

It is a further object of the invention to provide a guard device for asyringe as described, which can be manufactured at a nominal cost andwhich is sturdy, easy to maintain in sanitary condition, and of pleasingappearance.

Another object of the invention is to provide a guard device for asyringe which may be quickly installed thereon and removed therefrom andwhich aiiords the practitioner complete control of the'plunger action ofthe syringe as well as directional control of the discharge needle.

The device of the present invention comprises, essentially, a tubularcasing adapted to receive and enclose that portion of the syringeextending below the finger-grip of the syringe, provision being made foroutward extension of the discharge needle through the wall of thecasing. The internal diameter of the casing is such. that an annularspace may extend around the body of the syringe, between the body andthe casing, so that the heated body is space-insulated. Guide means areprovided for holding the syringe body centrally within the insulatingspace, and these guide means are resiliently brought into contact withthe syringe body so as frictionally to resist and control lengthwiserelative movement of the syringe and the casing. As the fixedfinger-grip of the syringe is brought into such proximity with the endof the casing as no longer to serve its original purpose, a finger-gripis providedcon the casing which may be rotated thereabout to obtain anydesired angle between the fingers of the practitioner and the dischargeneedle and may be wedged into temporarily fixed relation withthe casingwhen the desired angular relation has been achieved.

The above and other features of this invention will be brought out inthe ensuing description of certain preferred embodiments thereof, orwill be apparent from such description, having reference to theaccompanying drawings, in which:

Fig. l is a view i perspective of a guard device embodying theprinciples of this invention, shown as containing a syringe in operativeposition;

Fig. 2 is a medial longitudinal sectional view of the guard device andsyringe shown in Fig. 1;

Fig. 3 is a bottom plan View;

Figs. 4, 5, and 6 are transverse sectional views taken on thcorrespondingly numbered lines of Fig. 2, the direction of view beingthe same in all instances, as indicated by the arrows;

Fig. '7 is a medial longitudinal sectional view of a modified form ofguard device,-in accordance with this invention;

Fig. 8 is a bottom plan view of the guard device shown in Fig. 7; and

Fig. 9 is a transverse sectional view taken on the line 9-9 of Fig. 7.

Referring to the drawings, and particularly to Figs 1 through 6, theguard device of this invention may comprise a tubular casing II, formedof metal or of a material of relatively low heat conductivity, such as asynthetic resin but possessing a moderate elasticity or springiness soas not to be brittle when slightly distorted. The casin II has acylindrical wall I2 defining an opening I3 at one end, provided with aflange I4, and has a slot I5 extending from a position adjacent theopening I3 toward the other end of the casing, preferably -to a positionnear said other end. Said other end of the casing preferably has anopening I6 formed with an inwardly turned margin IT. A narrower slot I8in the margin I7 connects the slot I5 and the opening I6. It willreadily be seen that the casing II may be easily formed from a tube ofmetallic or plastic material having its one end spun outwardly to formthe flange I4 and its other end spun inwardly to form the margin I1, andwith the slots I5 and I8 milled as described.

Disposed between the openin I3 and the adjacent end of the slot I5, thecasing I I has a plurality of outward protuberances I9 which may bepunched or pressed in the wall I2 and which form shoulders for retaininga finger-grip 29 between them and the flange I4. The fingergrip 20 isformed with a collar portion 2! fitting, loosely, the casing I I andprovided with laterally and oppositely extending tabs 22 for convenientengagement by the fingers of the practitioner. In the spinning operationof forming the flange I 4, the casing II is slightly distended or belledbetween the protuberances I9 and the flange I4 to form a conical bearing23, upon the narrow end of which the finger-grip 2!] is rotatable andupon the wider end of which the fingergrip may be temporarily bound by aslight pressure in that direction.

The casing II is internally dimensioned to receive, freely, a syringe 25through the opening I3 and to afford an annular space 25 between thewall I2 and the body portion 2! of the syringe. A plurality of inwardprotuberances 28 on the inner surface 29 of the wall I2 extend into theannular space 26 and hold the body portion 2! centrally within thecasing II so that the annular space 26 encompasses the bodv portion 21with substantially uniform space: insulation. As illustrated, theprotuberances 281 are grouped in two longitudinally spaced groups,,

each of which comprises three protuberances spaced oircumferentially atone hundred and twenty degrees. Such grouping of the protuberances 28provides adequate support and retention of the body portion 2'! withinthe casing H, with a minimum number of points of contact across theinsulating annular space 25, but it will be understood that any arrangement of protuberant members serving the abovestated purpose is withinthe scope of the invention.

The syringe 25 herein illustrated and described is more or lessconventional, and may comprise, in addition to the body portion 2'l, aplunger 30 provided at one end with a plunger head SI and at its otherend with a handle 32. formed as a disc for convenience either ingripping with the fingers or in pressing with the flat of the hand orthe thumb. The plunger 33 extends throu h a cylinder head 33 into thebody portion 2? which is closed at its compression end by a secondcylinder head 34 having an opening 35 in which is set a hollow dischargeneedle 33. At least one of the cylinder heads is threadedly secured tothe body portion 21 to permit removal thereof for filling the syringe,and in the syringe shown both heads 33 and 34 are so secured. Thedischar e needle 36 is set at an angle to the axis of the casing I I andextends outwardly through the slot I5 which is sufficiently widethroughout its length to permit the nee le 36 to slide therein.

The cylinder head 33 has an extended hollow shank 3'! forming a bearingfor the plunger 30 and provid d at its free end with an outwardlyprojecting member or flan e 38 ri idly secured th reto, said m mberbeing generally discshaped. The member 38 is u ed as a fingergrio in theconventional un uarded syrin e in coniunction with the handle 32 as ameans of gr sping and o erat ng the syringe, and also serves as handlemeans for un crewing the cylind r he d 33 from the body portion 21 topermit rem val of the plun er 30. In the inst nt con truction the memb r38 serves the latter pur o e and al o pre erablv serves as a stop tolimit the entry of the syringe 25 into the c sing II, althmwh other stopmeans are available, such as contact of the cylinder head 34 with theinwardly turned margin IT, or contact of the needle 36 with the end ofthe slot I5. The use of the member 38 as a sto is particularly advantaeous in order to minimize contact and resulting transfer of heat betweenthe heated syringe and the portion of the guard device that is subjectto contact with the patients mouth.

To use the syringe '5, as protected b the casing II. for its intendedpurposes in dentistry, the o erator first fills the bo y portion 21 witmasses of solidified heat-fluidizable impression-material, for thatpurpose removing and then replacing one of the cylinderv heads such. ashead 34. and plac s the syrin e in boilin water. When the containedimpression-material has become sufliciently fluent, the syrin e isremoved from the water and the needle end thereof is inserted in thecasin I I throu h the openin I3. The syrin e is held tilted in relationto the casing during the initial sta e of entering it in the casing. topermit t e needle 35 to enter the slot I5 past the flange It and the uper part of the wall I2. When the needle 3' has been engaged in the slotI5, the syrin e is thrust into the casing by pressure applied to theconventional finger-tip member '38 in order not to apply pressureprematurely to the plunger 36. When the cylinder head 34 encounters theupper group of protuberances 28, it will receive therefrom frictionalresistance to its further entry into the casing. but continued pressureon the finger-tip member 38 will cause the wall I2 to dilate aspermitted by its elasticity and the slots I5 and I3 and the opening I6,thus allowing the cylinder head 34 to pass first the upper group ofprotuberances 28 and then the lower group and to proceed until furtherentry is stopped by contact of the member 38 with the flange I4. Theelasticity of the wall I2 causes the protuberances 28 to grip the bodyportion 21 so as to prevent the syringe from sliding out of the casinexcept in consequence of intentionally applied force.

With the heated body portion 21 and cyl nder head shank 31 enclosed inthe casing I I as abovedescribed, the casing may be comfortably touchedto even the tender membranes of the mouth, due to the space-insulationprovided by the annular space 26. Grasping the casing II with the handis not, however. necessary, as the combined unit mav be manipulated bymeans of the finger-grip 2i! and the handle 22. The fingergrip as may berotated upon the conical hearing 23 to assume any convenient angle inrelation to the discharge needle 36, and when such a convenient anglehas been established, the initial fiexion of the hand. to force theplunger head 3! a ainst the heat-fluent impression material will alsodraw the finger-grip 211 towards the expanded end of the conical bearing.23 and bind the fingerrip on the bearing at the selected angle.Continued manual pressure against the handle 22 causes the plunger headSI to exert pressure against the heat-fluidified impressionmaterial andthus to extrude such material through the discharge needle 36.

The syringe 25 may be withdrawn from the casing !I by grasping eitherthe handle '32 or the member 35 with one hand while the fin ers of theother either rasp the wall E2 or are hooked over the upper side of thefinger-grip 20. The distance between the flange I4 and the outwardprotuberances I9 is such that the finger-grip 20 may be retracted fromthe member 38 sufficiently to permit insertion of the finger tips underthe latter. The protuberances I9 serve as shoulders against which thefinger-grip may be pressed to exert the force necessary to withdraw thesyringe from the grip of the inward protuberances 28, and also serve atall times to bar the finger-grip 20 from the vicinity of the slot I5 andso from contact with the discharge needle 36. It will be appreciatedthat it is desirable to keep elements handled by the practitioner notonl out of contact with the patients mouth but also out of contact withother parts such as the discharge needle which enter the mouth.

In Figs. 7, 8, and 9 I have illustrated a modified embodiment of myinvention in which the casing of the guard device need not be of elasticmaterial. other resilient means being provided for causing the syringeto be gripped by the casing in the desired relative position. A casing49 has a cylindrical wall 4i provided at its upper end with a fiange I4,conical bearing 23 and outward protuberances I9, and at its lower endwith an opening I6 and inwardly turned margin I1, and with a slot I5extending from below the protuberances I9 to the vicinity of the openingI6, as in the preferred embodiment of my invention, but devoid of thenarrow slot [8 of the preferred embodiment. The opening I6 is notnecessary, as no elastic distortion is required of the casing 49, butits inclusion permits the casing to be made of tubing by a simplespinning and milling operation. A finger-grip Z0 is carried rotatablyupon the conical bearing 23.

Inward protuberances 42 on the inner surface of the wall M extendinwardly to engage the body portion of a syringe, the illustration ofwhich is not repeated, the arrangement in the present instance beingthat of upper and lower groups of two protuberances 42 each, with theprotuberant members of each group spaced approximately one hundred andtwenty degrees apart circumferentially, and in longitudinal alignmentwith the members of the other group. A leaf spring 43 is disposed in theplace occupied by the third protuberances in my preferred embodiment,this spring substituting not only for the third protuberances of eachgroup but for the elasticity provided by the wall and slot structure ofmy preferred embodiment. The spring as is secured at one end, preferablythe upper end, to the wall 4| as by spot welding in the instance of ametallic wall as shown at 44. When a syringe is placed within the casing40, the spring 43 yields to permit entry of the syringe, the free end ofthe spring sliding on the wall M, and then holds the syringe in properalignment and in spaced relation to the casing ii] to achievespace-insulation between the syringe and the casing, at the same timecreating frictional resistance to accidental withdrawal of the syringe.Otherwise the operation and manipulation of this modified embodiment ofmy invention is substantially identical with that previously describedin connection with the preferred embodiment.

Obviously my invention is subject to other modifications andarrangements of parts, hence I do not choose to be limited to theabove-described examples, but rather to the scope of the appendedclaims.

I claim:

1. A guard device for a syringe for use with heat-fluent materials, saidsyringe having an elongated hollow body for holding said materials, aplunger movable in said body, handle means on said plunger, and a hollowneedle forming an outlet from said body inclined at an angle to thelongitudinal axis thereof, comprising: a casing for said body havingwall means substantially enclosing said body and having an opening atone end for entry of said body thereinto, and having an internaldiameter greater than the external diameter of said body; friction meanson the interior of said casing engageable with said body so as toresist, while still permitting, longitudinal movement of said bodyrelative to said casing and so arranged as to hold said body annularlyspaced from said wall means; and a finger-grip on the extericr of saidcasing adjacent said opening adapted to cooperate with said handle toform a hand grip; said casing having a slot extending between positionsadjacent said finger-grip and adjacent the other end of said casingthrough which said needle may extend.

2. A guard device for a syringe for use with heat-fluent materials, saidsyringe having an elongated hollow body for holding said materials, aplunger movable in said. body, handle means on said plunger, and ahollow needle forming an outlet from said body inclined at an angle tothe 1onitudinal axis thereof, comprising: a casing for said body havingwall means substantially enclosing said body and having a first openingat its one end for entry of said body thereinto and having an internaldiameter greater than the external diameter of said body; said wallmeans defining a second opening in the other end of said casing and aslot extending from said second opening to a position adjacent saidfirst opening, said slot having a portion capable of allowing passage ofsaid needle therethrough, and said wall means being formed of resilientmaterial and biased to resist lateral expansion of said slot; andprotuberances on the inner surface of said wall means adapted by thebias of said wall means to hold said body annularly spaced from saidwall means while permitting relative longitudinal movement of saidcasing and said syringe.

3. A guard device for a syringe for use with heat-fluent materials, saidsyringe having an elongated hollow body for holding said materials, aplunger movable in said body, handle means on said plunger, and a hollowneedle forming an outlet from said body inclined at an angle to thelongitudinal thereof, comprising: a casing for said body having wallmeans substantially enclosing said body and having a first opening atits one end for entry of said body thereinto and having an internaldiameter greater than the external diameter of said body; said wallmeans defining a second opening in the other end of said casing and aslot extending from said second opening to a position adjacent saidfirst opening, said slot having a portion capable of allowing passage ofsaid needle therethrough, and said wall means being formed of resilientmaterial and biased to r sist lateral expansion of said slot;protuberances on the inner surface of said wall means adapted by thebias of said Wall means to hold said body annularly spaced from saidwall means while permitting relative longitudinal movement of saidcasing and said syringe; and a finger-grip member rotatably carried bysaid casing adjacent said one end, the exterior surface of said wallmeans there forming a wedge bearing for said member upon which saidmember may be temporarily bound to prevent relative rotation of saidmember and said casing.

4. A guard device for a syringe for use with heat-fluent materials, saidsyringe having an elongated hollow body for holding said materials, aplunger movable in said body, handle means on said plunger, and a hollowneedle forming an outlet from said body inclined at an angle to thelongitudinal axis thereof, comprising: a casing for said body havingWall means substantially enclosing said body and having an opening atits one end for entry of said body thereinto and having an internaldiameter greater than the eX- ternal diameter of said body;protuberances on the inner surface of said wall means spacedcircumierentially thereon so as to hold said body spaced from oneinternal sector of said wall means; a spring disposed Within said casingso as to urge said body into contact with said protuberances and out ofcontact with the remaining internal sector of said wall means; andorifice means for the passage of said needle from the interior to theexterior of said casing.

5. A guard device as set forth in claim 4, in which said orificemeans isa slot extending longitudinally of said casing so as to guide saidneedle in a radial direction relative to said casing; and includingadditionally a finger-grip member mounted on said casing and rotatableabout the longitudinal axis thereof, said casing having an expandedportion adapted to wedge said member to prevent relative movement ofsaid casing and said member; and means barring access of saidfinger-grip member to the vicinity of said slot.

HENRY F. BOEGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS N mic-er Name Date 368,627 Threlfall Aug. 23, 1887637,405 Papendell Nov. 21, 1899 FOREIGN PATENTS Number Country Date18,662 Great Britain of Sept. 15, 1905

